By Regina Hing, CNBC.com
For all the criticism lobbed at Hollywood over "greenwashing," there are a few true champions of nature among the rich and famous - and these 15 exemplify that.
We trawled through celebrity track records to see how involved they have been in eco causes in recent years, and weeded out ones who have not actively participated in the movement lately. We looked for people who weren't happy just donating time or money to environmental charities, but those whose work (and name) had as profound an impact on the drafting of a bill or the success of a project. We singled out celebrities who were honest about their limitations and consistent in their actions (Harrison Ford may have been the vice chair of Conservation International, but he also reportedly owns seven private aircraft).
What these stars have done is used their fame and wealth to raise awareness about the various conservation issues of their choosing-and, more importantly, set an example-such that thanks in part to them, support for environmental causes has never been as high as it is today.
See the slideshow: Top 15 Green Celebrites
The mega-model was hailed the Best Green International Celebrity in December Gisele Bundchen
The mega-model was hailed the Best Green International Celebrity in December, winning the online poll by a large margin, thanks to her work in ecological conservation and education.
Through her eco-friendly flip-flop line - Ipanema Gisele Bundchen - the supermodel has raised funds for conservation efforts in the Amazon and Atlantic Rainforest.
She also launched the Clean Water Project with her family, whose mission is to restore vegetation and the microbasins in her hometown of Horizontina, Brazil. In 2011, Harvard's Center for Health and Global Environment named her the year's Global Environmental Citizen, and in January this year, she made her first official visit to Africa as Goodwill Ambassador for the United Nations Environment Program.
DiCaprio actively serves on numerous environmental boards including the Natural Resources Defense Council, Global … Leonardo DiCaprio
As an environmentalist, DiCaprio is best known for having co-written, produced, and narrated the global warming film "The 11th Hour." But long after the credits rolled, his own Leonardo DiCaprio Foundation continued to lobby hard for a variety of environmental and humanitarian issues, including forest preservation, healthy oceans, clean water access, and renewable energy.
DiCaprio actively serves on numerous environmental boards including the Natural Resources Defense Council, Global Green USA, World Wildlife Fund and the International Fund for Animal Welfare. On top of sizeable donations he's committed over the years, the superstar actor has also pledged to forgo private jets and drives a Prius.
The actress and her husband, Andrew Upton, were key proponents of Greening the Wharf. Cate Blanchett
As co-artistic directors of the Sydney Theater Company, the actress and her husband, Andrew Upton, were key proponents of Greening the Wharf, a project that oversaw 1,900 solar panels being installed in The Wharf Theatre at Sydney's Walsh Bay. This now provides 70 percent of the theater's electricity requirements and, together with a system for rainwater harvesting, will eventually turn it fully carbon neutral. Under her guidance, the theater also started reusing and recycling costumes and props.
Although the Oscar winner and face of Australia's "Who on Earth Cares" program recently came under fire for appearing in the Australian government's carbon tax ads, Blanchett says she will "not be deterred from spreading the message about climate change".
Since 2008, the Environmental Media Awards of 2006 honoree has been using biodiesel-powered tour buses Maroon 5
Another Grammy-winning band committed to green touring. Since 2008, the Environmental Media Awards of 2006 honoree has been using biodiesel-powered tour buses, promoting recycling at its concert venues, and donating a portion of ticket sales to Global Cool, an environmental charity that works with entertainers. Maroon 5 has also played at Live Earth and headlined the Greenbuild International Conference & Expo last year. The bestselling artists are also strong supporters of the Environmental Media Association, Kiva, and Teen Impact.
The Edward Norton
The "Incredible Hulk" star flexes his green muscle in a broad range of initiatives, starting with his work as the United Nations Goodwill Ambassador for Biodiversity. At his designation ceremony in 2010, Norton spoke about how environmental issues are the "defining challenge of this era".
Norton is widely recognized for his work on the BP Solar Neighbors Program, which matches each celebrity purchase of a solar-energy home with solar panels for a low-income family home.
The 42-year-old has also been vocal with his support of The Wilderness Society and Earthjustice, and lent his hosting talent to a National Geographic series called Strange Days on Planet Earth. He has also been an active board member of Friends of the High Line, a group that campaigns to save and rebuild green space in New York City.
Apart from his well-documented humanitarian efforts, the Brad Pitt
Apart from his well-documented humanitarian efforts, the "Moneyball" star is also a longtime environmentalist. His Make It Right Foundation is on track to finish 150 homes in New Orleans, where all the new residences will not only sport environmentally sound features, but they will also use advanced engineering to withstand strong winds and floods. The U.S. Green Building Council lauded the star for his role in establishing "the largest and greenest single family community in the world." Pitt has donated more than $5 million to this project alone and, through the Jolie-Pitt Foundation, also helps oil the engine for various other natural resources and wildlife conservation campaigns.
See the full list: Top 15 Green Celebrities
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By Regina Hing, CNBC.com